JP7216585B2 - centrifugal fan - Google Patents

Description

The present invention relates to centrifugal fans.

A centrifugal fan is known as a blower that is widely used for cooling, ventilating, and air-conditioning home appliances, OA equipment, and industrial equipment, and air-conditioning and blowing air for vehicles. As a conventional centrifugal fan, the case consists of an upper casing (first case portion) and a lower casing (second case portion), and an impeller is housed between the upper casing and the lower casing. There is known a centrifugal fan that blows air sucked in from an upper casing and a lower casing outward from an opening formed in a side surface between the upper casing and the lower casing (see, for example, Patent Document 1).

In FIG. 5 of Patent Document 1, a metal bearing sleeve having a pair of ball bearings fitted inside is fitted inside a bearing holder integrally formed with a lower casing. One ball bearing is preloaded.

Normally, in this type of centrifugal fan, the amount of air blown by the centrifugal fan is adjusted by changing the rotation speed of the motor. Therefore, the vibration of the motor also changes according to the number of rotations of the motor. Motor vibration is electromagnetic vibration that occurs between the motor's stator coil and magnet. This electromagnetic vibration propagates to the casing via the ball bearings that rotatably support the shaft, generating vibration and noise in the centrifugal fan. do. In addition, vibration caused by the ball bearing itself is propagated to the casing, causing vibration and noise in the centrifugal fan.

In order to reduce the above-described vibrations, it has been practiced to mount an elastic material such as rubber on the outer ring of the bearing that supports the rotating shaft to reduce the propagation of the vibration from the bearing. For example, a rolling bearing has been proposed in which an elastic material such as rubber is mounted between a bearing that supports a rotating shaft and a housing that mounts the bearing to reduce the propagation of vibration from the bearing (for example, patent Reference 2).

JP 2018-155188 A JP-A-2000-192979

In the centrifugal fan of Patent Document 1, a constant pressure preload is applied by preloading the ball bearing with a preload spring in order to reduce the vibration of the bearing. It is difficult to arrange a structure in which an elastic material such as rubber that absorbs vibration is in contact with.

In view of this background, it is an object of the present invention to suppress propagation of bearing vibrations to a casing in a centrifugal fan having a structure in which the outer circumference of the outer ring of the bearing is fixed.

The present invention comprises: a first tubular member having an outer ring of a ball bearing fixed inside; an elastic member arranged in contact with the outer periphery of the first tubular member; a contacting second tubular member, a shaft rotatably held by the ball bearing, and a casing holding the second tubular member , the first tubular member is a centrifugal fan provided with a through hole for confirming the position of the ball bearing .

Here , the through-hole may be provided at a position where the axial end of the ball bearing can be seen. Further, there is an aspect in which an adhesive is applied from the through hole for fixing the outer ring of the ball bearing to the first cylindrical member. A plurality of the ball bearings are spaced apart in the axial direction, a plurality of the elastic members are spaced apart in the axial direction, and the through holes are spaced apart in the axial direction. provided between adjacent elastic members.

ADVANTAGE OF THE INVENTION According to this invention, in the centrifugal fan of the structure which fixed the outer periphery of the outer ring|wheel of a bearing, it is suppressed that the vibration of a bearing propagates to a casing.

1 is a cross-sectional view of a centrifugal fan according to an embodiment; FIG. FIG. 2 is a partially enlarged view of FIG. 1; FIG. 3 is a cross-sectional view of members constituting the centrifugal fan of the embodiment; FIG. 3 is a cross-sectional view of members constituting the centrifugal fan of the embodiment; FIG. 3 is a side view of members that constitute the centrifugal fan of the embodiment;

(composition)
FIG. 1 is a cross-sectional view of a centrifugal fan 100 using the invention cut along a plane including the shaft. FIG. 2 is a partially enlarged sectional view enlarging a part of FIG. Hereinafter, the axial direction means the direction in which the shaft 125, which is the rotating shaft, extends, and the radial direction means the direction orthogonal to the axial direction. Further, "up" means the direction of the upper casing 110 seen from the lower casing 130 when viewed from the viewpoint of FIG. 1, and "down" means the opposite direction.

The centrifugal fan 100 has a casing 150 composed of an upper casing 110 made of resin and a lower casing 130 made of resin. The upper casing 110 and the lower casing 130 are connected by a strut 140, and a resin impeller 120 is housed between the upper casing 110 and the lower casing 130 in a rotatable state.

A suction port 111 is provided in the center of the upper casing 110 . The upper casing 110 and the lower casing 130 are resin moldings, and the upper casing 110 and the struts 140 are integrally formed as one piece. A connector housing 131 is integrally formed with the lower casing 130 by integral molding. The connector housing 131 is provided with terminal pins 134 for external electrical connection to a circuit board 133, which will be described later.

Upper casing 110 and lower casing 130 are connected by a strut 140 interposed between upper casing 110 and lower casing 130 . A portion of the side surface of the casing 150 excluding the strut 140 forms a gap between the upper casing 110 and the lower casing 130 , and this gap portion serves as the outlet 112 .

In this example, a boss (resin pin) is formed at the tip of the support 140 on the upper casing 110 side, and this boss is inserted into a through hole formed in the lower casing 130. In this state, the tip of the boss is exposed to heat, infrared rays, The upper casing 110 and the lower casing 130 are connected via the struts 140 by crushing and crimping.

As the joining method, a form using welding by ultrasonic waves is also possible. Moreover, as the above-mentioned coupling method, it is possible to adopt a structure in which a tapping screw is inserted into the column 140 from the lower casing 130 side and tightened.

The impeller 120 is made of resin and is composed of an annular shroud 121 , a main plate 122 and a plurality of blades 123 arranged between the shroud 121 and the main plate 122 . The blades 123 are all backward-facing blades having the same shape and are evenly arranged in the circumferential direction.

The impeller 120 is integrally formed with an annular rotor yoke 124 made of a soft magnetic material (for example, iron material) and a metal shaft 125 serving as a rotating shaft. That is, resin impeller 120 is produced by insert-molding rotor yoke 124 and shaft 125 .

The impeller 120 has a boss 126 protruding toward the suction port 111 , and the shaft 125 is embedded in the boss 126 . An annular protrusion 127 is formed on the lower surface of the boss 126 so as to protrude in the axial direction. An annular magnet 128 serving as a rotor magnet is fixed to the inner peripheral surface of the rotor yoke 124 using an adhesive.

A stator core 161 that constitutes a stator 160 is arranged inside (on the shaft center side) of the ring-shaped magnet 128 with a gap therebetween. The stator core 161 is made by laminating thin plate-like soft magnetic materials such as electromagnetic steel sheets, has an annular shape, and has a plurality of salient poles (magnetic poles) provided on the outer periphery. A resin insulator 162 is attached to the stator core 161 , and a stator coil 163 is wound around each salient pole via the insulator 162 .

A tubular bearing holder 170 is fixed to the lower casing 130 , and a stator core 161 is fixed to the outer circumference of the bearing holder 170 . A flange 171a is provided on the outer periphery of the bearing holder 170, and the stator core 161 is fixed using a stepped portion at the upper end of the flange 171a.

The bearing holder 170 has a tubular shape and holds an elastic material for absorbing vibration inside. That is, the bearing holder 170 has a vibration absorbing function. The bearing holder 170 is composed of a hollow cylindrical outer sleeve 171, a hollow cylindrical inner sleeve 172 arranged inside the outer sleeve 171, and an elastic member 173 arranged between the outer sleeve 171 and the inner sleeve 172. It is Details of the bearing holder 170 will be described later.

Stator 160 is configured by stator core 161 , insulator 162 and stator coil 163 . A rotor 129 is configured by the rotor yoke 124 and the magnets 128 . The rotor 129 is integrated with the impeller 120 , and the impeller 120 rotates together with the rotor 129 . The stator 160 and rotor 129 constitute an outer rotor type brushless DC motor. Although shaft 125 is embedded in boss 126 , rotor yoke 124 may be coupled to shaft 125 .

The lower casing 130 has a flat cylindrical structure with a bottom and has a recess 132 . A circuit board 133 is accommodated in the recess 132 . The circuit board 133 is fixed to the lower casing 130 and has a drive circuit that supplies a drive current to the stator coil 163 .

Ball bearings 181 and 182 are mounted inside an inner sleeve 172 that constitutes the bearing holder 170 , and the ball bearings 181 and 182 hold the shaft 125 inside the bearing holder 170 in a rotatable state.

A flange 172a is formed inside the inner sleeve 172 that constitutes the bearing holder 170, and the lower end of the coil spring 183 is in contact with the stepped portion at the upper end of the flange 172a. The upper end of the coil spring 183 contacts the lower end of the outer ring 181a of the ball bearing 181 and elastically presses the outer ring 181a upward. The upper end of the inner ring 181b of the ball bearing 181 is in contact with the tip of the projecting portion 127 projecting downward from the boss 126. As shown in FIG.

A preload is applied to the ball bearing 181 by the coil spring 183 . That is, the outer ring 181a of the ball bearing 181 is pushed upward by the coil spring 183, so that the inner ring 181b of the ball bearing 181 is pressed against the protrusion 127, thereby preloading the ball bearing 181. As shown in FIG.

(motion)
When the impeller 120 rotates by being driven by a motor having a stator 160 and a rotor 129, air is sucked into the casing 150 from the suction port 111 along with the rotation. It passes through the gap and blows out radially outward from the impeller 120 and then out of the casing 150 from the outlet 112 .

(bearing holder)
The bearing holder 170 will be described below. The bearing holder 170 has an outer sleeve 171 made of metal and an inner sleeve 172 made of metal, and an elastic member 173 is arranged between the outer sleeve 171 and the inner sleeve 172 . As the elastic member 173, a material that is elastically deformable, such as silicone rubber or synthetic rubber, is used. A pair of ball bearings 181 and 182 are fixed inside the inner sleeve 172 . The outer races of the ball bearings 181, 182 are fixed inside the inner sleeve 172 by press fitting, gluing, or a combination thereof.

The elastic member 173 is formed to cover the outer circumference of the inner sleeve 172 and is fixed to the outer circumference of the inner sleeve 172 . A part of the outer circumference of the inner sleeve 172 is not formed with the elastic material 173 . A portion of the inner sleeve 172 where the elastic member 173 is not partially formed is formed with a through-hole penetrating from the outside to the inside (a through-hole penetrating the outside and inside of the cylindrical structure).

FIG. 5 shows an example of inner sleeve 172 covered with elastic material 173 . In the example of FIG. 5, the elastic member 173 is composed of band-shaped elastic members 173a, 173b, and 173c formed at three locations, upper, middle, and lower, respectively. A through hole 172b is formed in the inner sleeve 172 between the belt-shaped elastic members 173a and 173b adjacent in the axial direction. A through hole 172c is formed in the inner sleeve 172 between the belt-like elastic members 173b and 173c adjacent in the axial direction. A plurality of through-holes 172b and 172c (for example, three at equal intervals) are formed in the circumferential direction.

In the example of FIG. 5, two rows in which the through holes 172b and 172c are formed are formed in the axial direction. The through hole 172b is formed at a position where the lower end of the outer ring 181a of the ball bearing 181 can be seen. The through hole 172c is formed at a position where the upper end of the outer ring 182a of the ball bearing 182 can be seen. By observing the position of the lower end of the outer ring 181a of the ball bearing 181 through the through hole 172b, the position of the ball bearing 181 relative to the inner sleeve 172 in the axial direction can be known. Further, by observing the position of the upper end of the outer ring 182a of the ball bearing 182 through the through hole 172c, the position of the ball bearing 182 relative to the inner sleeve 172 in the axial direction can be known. A configuration is also possible in which the elastic material is not formed only in the portion of the through hole. FIG. 2 shows an example of such a case.

Further, the outer ring 181a of the ball bearing 181 can be fixed inside the inner sleeve 172 by applying an adhesive from the through hole 172b. Similarly, the outer ring 182a of the ball bearing 182 can be fixed inside the inner sleeve 172 by applying an adhesive from the through hole 172c.

(Manufacturing process)
FIG. 3 is a cross-sectional view showing a state in which the shaft 125 coupled with the impeller 120 is attached to the sub-assembly in which the ball bearings 181 and 182 are attached to the inner sleeve 172. As shown in FIG. FIG. 4 is a cross-sectional view showing a state in which the outer sleeve 171 is attached to the lower casing 130. As shown in FIG. FIG. 5 is a side view of inner sleeve 172 covered with elastic material 173 and having ball bearings 181 and 182 mounted therein.

First, the resin upper casing 110 is integrally formed with the strut 140 by resin injection molding (see FIG. 1). Also, the resin lower casing 130 is integrally formed by inserting the metal outer sleeve 171 (see FIG. 4). An annular groove 171b is formed in the outer circumference of the outer sleeve 171 so that the connection with the resin-made lower casing 130 becomes stronger.

After obtaining the lower casing 130 in which the outer sleeve 171 is inserted, the circuit board 133 is fixed to the lower casing 130, and the stator 160 is assembled to the outer sleeve 171 to obtain the lower assembled member shown in FIG.

On the other hand, as shown in FIG. 3, the inner ring 181b of the ball bearing (upper ball bearing) 181 on the impeller 120 side is press-fitted onto the shaft 125 coupled with the impeller 120 . Thus, the ball bearing 181 is fixed to the shaft 125 integrated with the impeller 120 .

Also, an inner sleeve 172 covered with an elastic material 173 is prepared. Note that the elastic member 173 is omitted in FIG. Then, the ball bearing (lower ball bearing) 182 on the lower casing side is press-fitted inside the inner sleeve 172 through the opening (lower side) on the lower end side of the inner sleeve 172 set in the jig. At this time, the ball bearing 182 is press-fitted inside the inner sleeve 172 so that the upper end of the outer ring 182a of the ball bearing 182 contacts the flange 172a (outer ring press-fitting). As a result, the outer circumference of the outer ring 182 a of the ball bearing 182 is fixed inside the inner sleeve 172 . At this time, if necessary, the outer ring 182a of the ball bearing 182 may be fixed to the inner sleeve 172 by applying an adhesive through a through hole 172c (see FIG. 5) formed in the inner sleeve 172. FIG.

Next, a coil spring 183 and a washer (not shown) are inserted inside the inner sleeve 172 through an opening (upper side) on the upper end side of the inner sleeve 172 . After that, the shaft 125 coupled with the impeller 120 is inserted inside the inner sleeve 172 from above.

At this time, the shaft 125 is press-fitted inside the inner ring 182 b of the ball bearing 182 fixed inside the inner sleeve 172 . Also, a ball bearing 181 fixed to the shaft 125 is inserted inside the inner sleeve 172 .

At this time, the axial position of the shaft 125 (impeller 120) with respect to the inner sleeve 172 is adjusted so that the outer ring 181a of the ball bearing 181 fixed to the shaft 125 is at a predetermined position on the shaft. This adjustment is performed through a through hole 172b formed in the inner sleeve 171 while confirming the position of the outer ring 181a. After that, the outer ring 181a of the ball bearing 181 is fixed to the inner sleeve 172 by applying an adhesive from the through hole 172b. In this way, an upper assembled member is obtained in which the impeller 120 is assembled to the inner sleeve 172 shown in FIG.

Next, the upper assembly member shown in FIG. 3 and the lower assembly member shown in FIG. 4 in which the stator 160 is assembled to the outer sleeve 171 fixed to the lower casing 130 are joined. Specifically, the inner sleeve 172 with the impeller 120 shown in FIG. 3 is press-fitted inside the outer sleeve 171 fixed to the lower casing 130 shown in FIG. The inner sleeve 172 is press-fitted inside the outer sleeve 171 , and the elastic member 173 is attached by pressing the inner side of the outer sleeve 171 . Thus, the centrifugal fan 100 of FIG. 1 is obtained. Moreover, a means for applying an adhesive to a portion where the elastic member 173 is not provided and fixing it may be used together.

(Superiority)
Since the elastic member 173 is interposed between the inner sleeve 172 and the outer sleeve 171, it is possible to suppress the propagation of vibration from the ball bearings 181, 182 to the lower casing . In addition, since a pair of ball bearings 181 and 182 are attached to the inner sleeve 172 in advance, and the shaft 125 to which the impeller 120 is coupled is attached, the ball bearings 181 and 182 can be sub-assembled, which improves workability in the manufacturing process. improves. Further, by providing the through holes 172b and 172c in the inner sleeve 172, the position of the outer ring 181a can be observed using the through holes 172b, and the adhesive can be applied while checking the application state through the through holes 172b and 172c. can be done.

In particular, the position of the ball bearing 181 in the axial direction with respect to the inner sleeve 172 is important in determining the preload value of the coil spring 182. Therefore, the preload value can be accurately determined by confirming the position through the through hole 172b. It is possible to control and obtain the characteristics of the bearing structure with good uniformity. Further, by inserting the outer sleeve 171 and integrally molding the lower casing 130 with resin, the position and orientation, particularly the orientation, of the bearing holder 170 can be determined with high accuracy.

DESCRIPTION OF SYMBOLS 100... Centrifugal fan, 110... Upper casing, 111... Suction port, 112... Air outlet, 120... Impeller, 121... Annular shroud, 122... Main plate, 123... Blade, 124... Rotor yoke, 125... Shaft, 126... Boss, DESCRIPTION OF SYMBOLS 127... Protrusion 128... Magnet 129... Rotor 130... Lower casing 131... Connector housing 132... Recess 133... Circuit board 134... Terminal pin 140... Post 150... Casing 160... Stator 161 ... stator core 162 ... insulator 163 ... stator coil 170 ... bearing holder 171 ... outer sleeve 171a ... flange 171b ... annular groove 172 ... inner sleeve 172a ... flange 172b ... through hole 172c ... through hole , 173... elastic member, 173a... belt-like elastic material, 173b... belt-like elastic material, 173c... belt-like elastic material, 181... ball bearing, 181a... outer ring, 181b... inner ring, 182... ball bearing, 182a... outer ring, 182b ... inner ring, 183 ... coil spring.

Claims (4)

a first tubular member having an outer ring of a ball bearing fixed therein;
an elastic member disposed in contact with the outer periphery of the first cylindrical member;
a second cylindrical member having an inner side contacting the elastic member;
a shaft rotatably held by the ball bearing;
a casing that holds the second tubular member ,
A centrifugal fan , wherein the first tubular member is provided with a through hole for confirming the position of the ball bearing . 2. The centrifugal fan according to claim 1 , wherein the through-hole is provided at a position where an axial end of the ball bearing can be seen. 3. The centrifugal fan according to claim 1, wherein an adhesive is applied from the through hole to fix the outer ring of the ball bearing to the first cylindrical member. A plurality of the ball bearings are spaced apart in the axial direction,
a plurality of the elastic members are spaced apart in the axial direction,
4. The centrifugal fan according to any one of claims 1 to 3 , wherein the through holes are provided between adjacent elastic members spaced apart in the axial direction.

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